Frequency changing system for radio transmitters



Feb. 7, 1933. L. A. GEBHARD ET AL FREQUENCY CHANGING SYSTEM FOR RADIO TRANSMITTERS 4 Sheets-Sheet 1 Filed July 31, 1929 awash: 61, $165M,

afyf TORNEY Feb. 7, 1933. 1.. A. GEBHARD T A FREQUENCY CHANGING SYSTEM FOR RADIO TRANSMITTERS Filed July 31. 1929 4 Sheets-Sheet 2 w. ATTORNEY 1933. L. A. GEBHARD ET AL 1,896,168 I FREQUENCY CHANGING SYSTEM FOR RADIO TRANSMITTERS Filed July 51, 1929 4 Shets-Sheet 3 Ila-1.

A TTORNEY Feb. 7, 1933. A. GEBHARD ET AL FREQUENCY CHANGING SYSTEM FOR RADIO TRANSMITTERS Filed July 31, 1929 4 Sheets-Sheet 4 4 amud'm QOMM a. 94/616444, (904x10 5?, 0 1%,

ATTORNE'Y Patented Feb'.- 7, 1933 UNirenfsrArES PATENT OFFICE.

LOUIS A. GEBHARD AND CORRIE F. RUDOLPH, OF WASHINGTON, DISTRICT OF COLUM- BIA, ASSIGNORS TO WIRED RADIO, INC., OF NEW DELAWARE ,YORK, N. Y., A CORPORATION OF FREQUENCY. CHANGING. SYSTEM FOR RADIO TRANSMITTERS Application and July 31,

changed from one channel to another channel which is displaced from the first channel by a relatively large portion of the frequency,

spectrum. I V

Still another ob]ect of this lnvention 1s to provide an arrangement 1n which switching devices cooperate withthe frequency chang ing devices of a high frequency signaling,

systemwhereby additional inductance or capacity units are e1ther connected into or (llS- connected from the oscillatory circuit ofthe signaling system. v v

A further obJect of this invention is to provide an arrangement 1n 'WlllCll circuit making and interrupting devices cooperate with the frequency changing devices of the signaling system for either connecting nto or disconnecting from the frequency determining circuits of the signaling system, additional capacity and inductance unit's.

Still a further object of this invention is to provide an arrangement wherebyat pre determined intervals of actuation of the frequency changing system of a signaling system, switchingdevic'es are actuated and additional inductance or capacity units are con? nected into the frequency determining circuits of the signaling system.

Other and further objects of this invention 1 will be apparent to those skilled in the art to whichthis invention relates, from the following specification and the claims.

According to this invention a frequency changing system employing an inductance of the type disclosed in the copending application of Louis A. Gebhard, Serial Number 1929. Serial No. 382,421.

327,984, now Patent No. 1,818,316, issued Au gust 11, 1931, for inductance systems, has incorporated therein a switching mechanism, oierable simultaneously with the changing o the value of the inductance, for inserting into circuit with the inductance either another inductance unit or a capacity unit whereby the signaling system employing the frequency changing system constructed in accordance with this invention is enabled to rapidly change its operating frequency over a considerable range of frequency channels.

In a radio signaling system operating over a Wide range of frequency channels, additional condensers and inductances must often be connected into circuit in order to obtain the range of frequency channels necessary. If, for example, it is desired to operate a signaling system in the 4000 kilocycle, 8000 kilocycle, 12000 kilocycle and the .16000kilocycle frequency channels it is usually necessary to either connect an additional condenser in parallel with the condenser normally used in the oscillatory circuit of the signaling system or to connect an additionalilr ductance in series with the inductance norwave changlng operation.

Referring to the drawingsbriefiy, Figure 1 illustrates a view in side elevation in partial cross-section of, an embodiment of this invention; Fig. 2 is a cross-sectional view along the line 2 2 of Fig. 1; Fig. 3 is a cross sectional view in front elevation of a modified form ofthis in ention; Fig. 4 is a detail view of the switching mechanism; and F 5 il lustrates a circuit arrangement.

In F ig; 1 of the drawings reference numeral 1 designates apanel member which may be either ofinsulating material or of conducting material such as is employed for electrical shielding purposes. Panel 2 of metal or insulating material is supported by the spacers 3 which are carried by the panel 1. A bearing element 4 is carried by the panel 2 for supporting the rotatable element 7. The

I beveled gear 6 is provided with a projecting portion 5 which is fitted into a hollow portion of the rotatable element 7 Another beveled gear .8, which is adapted to engage the gear 6, is mounted upon the shaft 9. An elongated and well machined bearing 10 is mounted upon the panel 2 for supporting the shaft 9. A gear 11 is mounted upon the shaft 9 for engaging the teeth 12 of the gear unit 13 which is mounted upon the shaft 14. The shaft 14 actuates an inductance wave changing unit 15. Upon rotating the shaft 14 the inductance-turn-engaging member 16 is caused to continuously, frictionally, engage the stationary turns 68 which are mounted upon the rods 13. The stationary threaded rod 65 engages set screw 66 carried in mounting member 67 whereon turn-engaging member 16 is mounted. Screw 66 slides in a longitudinal slot in sh aft 14. As handle 49 retates shaft 14, screw 66 slides longitudinally along shaft 14, and turn-engaging member 16 slides around the successive stationary turns 68 which are mounted on rods 18, facilitated by the movement of screw 66 and mounting member 67. A variable capacity unit may be employed in place of the inductance system 15 where it is desired to vary the capacity of the frequency determining circuit instead of the inductance. Rings 19 and 20 are mounted upon the rotatable element 7. Set screws 21 and 22 are employed to fixedly position the rings 19 and 20 with respect to the element 7. A pin 23 is positioned upon the ring 20 for engagement with the notch 24a in the end of the member 24 which is carried by the switching member 25 upon which is mounted the switch blade 26.

Contact members 27 and 28, for receiving the switch blade 26 and completing electrical circuit therewith, are supported in position by the members 29 and 30, respectively. Binding posts 31 and 32 are provided for the members 29 and. 30. Panel members 33 and 34 of insulating material, are supported upon the panel 2 by brackets 36 and 37 which cooperate with the spacers 38 and 39 and screws 38a and 39a associated therewith. Spacers 35, 35', 41 and 41 of insulating material, are positioned between the panel memhers-33 and 34 for rigidly holding the panels together. Members 42 and 43 are supported by the panels 34 and 33, respectively for engagement with the switching member 24 and for serving as a bearing for the switching member. Springs 44 and 45 are attached to the bearing members 42 and 43 and the pins 46 and 47 which are positioned upon the arm 25 for causing the switching member 25 to suddenly establish or interrupt the electrical member 7. Conventional indications are registered upon the dials 48 and 50. A window 51 is provided in the panel 1 whereby the indications of the dials 48 and 50 may be viewed and the position of the inductance 15 and the pin 23 may be determined.

In Fig. 2 of the drawings a cross-sectional view in front elevation is illustrated. The dials 48 and 50 are partally broken away in order to more clearly illustrate the position of the gear 11 which coacts with the worm gear 13 in the actuation of shaft 9.

In the modification of. this invention illustrated in Fig. 3, an additional switching unit B similar to the unit A is provided. The units B and C may be angularly displaced from the position of unit A as shown. The pin 23 mounted upon the ring 20 will not engage theactuating levers 52 or 53 but the pin 54 which is mounted upon the ring 19 will engage the levers 52 or 53 because they operate in different planes. Spacer members similar to members 38, illustrated in Fig. 1 are not employed in supporting switching units B or C, these units are consequently mounted directly upon the panel 2. If it is desired the spacers 38 may be eliminated from the supporting arrangement of switch A and the switch may be mounted directly upon the panel 2 in which case the pin 23 would pass through slot 24?) in the member 24 while the pin 54 engages with the sides of the projection 24a. The pin 23 will cause the operation of either unit B or C. This arrangement necessitates the use of spacers 38 and 39 to cause proper alignment of slot 24a with pin 23.

A detail cross-sectional view of the switching mechanism taken along the line 44 of Fig. 1 is illustrated in Fig. 4. The switch blade 26 is shown engaging the contact 27. By actuating the pin 23 and moving the lever 24 the arm 25 is suddenly caused to rotate about the bearing 42 as an axis and the switch blade 26 caused to engage the contact 27a. The spacers 35, 35, 41 and 41 may be provided with sleeves of highly resilient material, such as rubber in order to reduce the shock to which the spacers may be subjected in the operation of the switch.

In operation the additional inductance or capacity unit to be connected into circuit or disconnected from circuit upon the actuation of the switch mechanism is connected to the switching mechanism. For example, as illus trated in Fig. 5, the terminal 56a of the additional inductance unit 56v may be connected I I o to the binding post 31a of the switch A, and

terminal 55a of the inductance 55, which is already connected into the anode. circuit of the shield gridelectron discharge device 58 is connected to the terminals 32 and 32a.

The positive'terminal' of the source of supply 57 is connectedto the terminal 566 of the inductance 56 and the terminal 31. When the terminals 31 and 32 are connected by the switch blade 26 the inductance 55 is alone in circuit. vVhenthe terminals- 31a and 32a are'connected the additional inductance 56 is connected into circuit with inductance55. A similar arrangement is employed whereby an additional condenser 60 may be connected in parallel with the condenser '59 by the switching mechanism B. Terminal 61 of the switching mechanism B is connected to'the condenser 59. Terminals 63 and 64 are connected to the condenser 60 which is to be connected in parallel withcondenser 59. The terminal 62 is connected to the condenser and the condenser 59. When the circuit 25 betweenthe terminals. 61 and 63 in the switching mechanism B is complete the condenser. 60 is connected ,in parallel with the con:

denser 59. When the circuit between terminals 62 and 64 is complete thecondenser 60 is short circuited. The inductance 55 may be controlled by the mechanism illustrated in Fig. lwhich is employed to controlthe' switching devices A and B.

While we have described our invention in itsprefcrred embodiment it is to be understood that many modifications thereof may be made without departing from the spirit range of wave lengths, a shaft, a continuously variable inductance, a contactor rotatable on said shaft and engaging said induc-- tance, a permanently connected'condense-r connected JIICII'CLllt with said variable 1nductance, a fixed inductance, a fixed condenser, a toggle switch connected for connecting said fixed inductance in circuit with said Variable inductance, a second toggle switch connected for connecting said fixed condenser in circuit with said permanently connected condenser, a rotating member, pins carried by said rotating member and posi tioned for respectively actuating said toggle shaft connects said fixed inductance and said fixed condenser in circuit.

2. In a tuning system for covering ,a wide range of wavelengths, a helical'inductance,

a contactor slidable along said helical inductance, a rotatable shaft carrying said contactor,a permanently connected condenser connected in circuit with said-inductance, a fixed inductance, a fixed condenser, a tog-' gle switch connected for connecting said fixed inductance 1n circuit with said helical inductance, a second toggle switch connected for connecting said fixed condenserln circuit with said permanently connected condenser, a rotating member, plns carried by S2l1d'I0- tating member and positioned for respectively actuating said toggle switches as said rotating member is rotated, and a system of gears for transmittingrotating motion between sai d shaft and said rotating member,

.whereby the rotation ofv said shaft connects said fixed inductance and said fixed condenser 1n circuit.

3. In a circuit "arrangement, an electron tube having cathode, grid and anode, an i11- put circuit connected to said grid, an output circuit connected to said anode, said output,

circuit comprisingga continuously variable inductance and a permanently connected condenser. a fixed lnductance, afixed c0n-.

denser, ashaft for varying said continuously variable inductance, a toggle switch connected for connecting said' fixed inductance in circuit with said variable inductance, a second toggle switch connected for connecting said fixed condenser in circuit with said pern1anently connected condenser, a rotating member, pins carried by said rotating member and positioned for respectively actuating said toggle switches as said rotating member isrotated, and a system of gears for transmitting rotative motion between said shaft andsaid rotating member, whereby the rotation of said shaft connectssaid fixed inductance and said fixed condenser in circuit and tunes said output circuit.

LOUIS A; GEBHARD. CORRIE F. RUDOLPH.

switches as said rotating member is rotated,

and a system of gears for transmitting rotating motion between said shaft and said rotat-u Y ing member, whereby .the rotation ofsaid I 

